The quest Lighthouse Keeper's Hospitality (TR_m4_T_Lighthouse) in Teyn can't complete upon Erethys' death. Couldn't find anything in his script or elsewhere to trigger Jounral TR_m4_T_Lighthouse 100 to finish the quest.

Another note: His GetDistance check on the player should be increased slighly. You can get close enough to interact with him to get the greeting choices, after he attacks he forcegreets the same choice message again.